Desensitizing of light sensitive silver halide emulsions



baths.

Patented Dec. 9, 1 941 nnsmssrrrzmc or LIGHT sENsrrrvn SILVER HALIDE EMULSIONS Emil Joachim Birr, Bitterfeld, Germany, assignor, by mesne assignments, to General Aniline & Film Corporation, New

tion of Delaware York, N. Y., a corpora- No Drawing. Application December 12, 1939, Se-

rial No. 308,825. 1938 Y 12 Claims.

This invention relates to the desensitization of silver halide emulsions. It is a known fact to use anthraquinone derivatives for the desensitizing of photographic emulsions. Especially effective are taurides of the anthraquinonesulfo or carboxylic acids, especially anthraquinone acid amides, at least one hydrogen atom of the amide group being substituted by a radical, containing sulfo or carboxyl groups. According to the U. S. Patent No. 2,172,192.. filed September 5, 1939, especlally ethers and thioethers of anthraquinone with aliphatic or aromatic radicals show excellent desensitizing qualities.

It has been found, that generally the qualities of the desensitizers of this class can be improved upon by using derivatives of anthraquinones, obtained by carbocyclic condensation with a triazole, as for instance anthraquinonetriazole, an- ,thraquinonetriazolesulto acid, anthraquinonetriazolecarboxylic acid, nitroanthraquinonetriazole etc., the two carbon atoms of the triazole nucleus condensed onto the anthraquinone nu- In Germany December 12,

formed by condensation of a triazole nucleus on-' to a carbocyclic ring of an anthraquinone nucleus.

2. A process for desensitizing light sensitive silver halide emulsions which comprises treating vsaid silver halide emulsions with a compound cleus being formed by two carbon atoms of one a of the benzene rings of the anthraquinone nucleus. The sulfo acids of these new compounds of the typical formula be added to in preliminary the developer or may be used Example 1 0.5 g; of 1,2-triazoleanthraquinone-3-sulfo acid 0.3 g. of 2,3-triazoleanthraquinone are dissolved in one liter developer. The orthoor panchromatic emulsions developed in this deformed by condensation of a triazole nucleus onto a carbocyclic ring of an anthraquinone nucleus selected from the group consisting of anthraquinone, anthraquinone sulfo acids, anthraquinone carboxylic acids and nitroanthraquinones.

3. A process for desensitizing light sensitive silver halide emulsions which comprises immersing said silver halide emulsions before development in an aqueous preliminary bath containing a compound formed by condensation of a triazole nucleus onto a carbocyclic ring of an anthraquinone nucleus.

4. A process for desensitizing light sensitive silver halide emulsions which comprises immersing said silver halide emulsions before development in an aqueous preliminary bath containing a compound formed by condensation of a triazole nucleus onto a carbocyclic ring 0! an anthraquinone nucleus selected from the group consisting of anthraquinone, anthraquinone sulfo acids, anthraquinone carboxylic acids and nitroanthraquinones.

5. A process for desensitizing light sensitive silver halide emulsions which comprises developing said silver halide emulsions in an aqueous solution of a developing agent and a compound formed by condensation of a triazole nucleus onto a carbocyclic ring of an anthraquinone nucleus.

6. A process for desensitizing light sensitive silver halide emulsions which comprises developing said silver halide emulsions in an aqueous solution of a developing agent and a compound formed by condensation of a triazole nucleus onto a carbocyclic ring of an anthraquinone nucleus selected fromv the group consisting of anthraquinone, anthraquinone sulfo acids, anthraquinone carboxylic acids and nitroanthraquinones.

7. As a desensitizer for light sensitive silver halide emulsions a compound formed by condensation of a triazole nucleus onto acarbocylic ring of an anthraquinone nucleus.

8. As a desensitzer for light sensitive silver halide emulsions a. compound formed by condensation of a triazole nucleus onto a carbocylic ring of an anthraquinonc nucleus "selected from the group consisting of anthraquinone, anthraquinone sulfo acids, anthraquinone carboxylic acids,

nitroanthraquinones.

9. A bath for desensitizing lightsensitive silver quinone carboxylic acids, and nitroanthraquinones.

11. A developer for developing light sensitive silver halide emulsion layers comprising an aqueous solution of a developing agent and a compound formed by .conden'sati'onof a triazole nucleus onto 'a carbocyclic ring of an anthraquinone nucleus.

* 12.-A developer for developing light sensitive halide emulsions containing a compound formed by condensation of a triazole nucleus onto a carbocyclic ring of an'anthraquinone nucleus.

10. A bath for desensitizing light sensitivesilver halide emulsions containing a compound formed by condensation of a triazole nucleus onto a carbocyclic ring oi! an anthraquinone nucleus selected from the group consisting of anthraquinone, anthraquinone sulfo acids, anthra- 

